1. Field of the Invention
The present invention relates to a method of determining frequency bands of a data storage system and an apparatus using the same, and more particularly, to a method of determining frequencies for reading and writing data from and to a disk drive while avoiding frequencies that have adverse effects on the system and to a disk drive using the same.
2. Description of the Related Art
Data storage capacity and the processing speed of a hard disk drive (HDD), which is a data storage system, is rapidly increasing. Accordingly, as the track per inch (TPI) and the bit per inch (BPI), which denotes recording density, of HDDs increases, the frequency used for reading and writing data also increases. In addition, distribution of frequencies used in data read and write is also becoming varied as an adaptive zone layout (AZL) technology, adjusted to the physical characteristics of a head, is being used.
Read and write frequencies used in a hard disk drive 10 shown in FIG. 1 are in proportion to the BPI of a disk(s) 12 and the rotating speed of a spindle motor 14. Therefore, since an outer region at the disk(s) 12 has a higher recording density than an inner region of the disk(s) 12, the outer region of the disk(s) 12 uses a higher frequency than the inner circumference. In addition, by setting a recording density differently according to the characteristics of a transducer 16 (also known as a head), various frequencies are used. Accordingly, a distribution of read and write frequencies used in a conventional hard disk drive is as illustrated in FIG. 2.
However, when using regular and continuous read and write (R/W) frequencies as illustrated in FIG. 2, the read and write frequencies may overlap with operational frequencies such as a mechanical resonance frequency, a clock frequency used in a printing circuit board (not shown) of which the hard disk drive 10 is composed, or a communication frequency used to communicate with a host apparatus. A mechanical resonance frequency may be generated by a head-gimbal assembly 22 and a base 36, for example.
In this case, the read and write (R/W) frequencies increase the level of noise by combining with at least one of the operational frequencies such as the resonant frequency, the clock frequency, or the communication frequency, which adversely effects the operations (functions) of the data storage system. In addition, the composition of the combined frequency causes a problem in electromagnetic compatibility (EMC) approval of a set mounted in the hard disk drive 10. Furthermore, the hard disk drive 10 is mounted in a personal computer (PC) or an audio/video apparatus when used, thereby causing electro-magnetic interference (EMI) by weakening coverage of or amplifying harmful frequencies according to a structure of a chassis or a cable of the set the hard disk drive 10 is mounted in.